As was first noted by Zakharov [1]}, in the kinetic equation (REF ) in the case of isotropic distributions, the dispersion contribution in \(\omega _{k}\)  can be neglected, despite the presence of the product of two delta functions with respect to frequencies and wave vectors in the collision term giving a singularity in the kinetic equation. This singularity in the kinetic equation turns out to be integrable after averaging over the angles. As a result, the kinetic equation admits a stationary power-law solution: \(n_{k}\propto \)  \(k^{\alpha }\) . The exponent \(\alpha \)  for the Kolmogorov-type spectrum is found using the Zakharov transformations (see [2]}): \(\alpha =-11/2\) , which corresponds to the Zakharov-Sagdeev spectrum [3]}:
\(E(k)=C\varepsilon ^{1/2}k^{-3/2}. \) 
